Feldgleichungen der T REDER schen Gravitationstheorie, die aus einem Variationsprinzip ableitbar sind. I

In the frame work of T REDER 's gravitational theory we consider two classes of field equations which are derivable from two classes of L AGRANGE ian densities Ω (1) (ω 1 , ω 2 ), Ω (2) (s̀ 1 , s̀ 2 ). ω 1 , ω 2 ; s̀ 1 , s̀ 2 are parameters. Ω (2) (ω 1 , ω 2 ) gives us field equations which are up to the post‐N EWTON ian approximation in the sense of N ORDTVEDT , T HORNE and W ILL equivalent to the field equations given by B RANS and D ICKE . For ω 2 = −1 −2ω 1 field equations follow from Ω (1) (ω 1 , −1 −2ω 1 ) which are in the above mentioned sense of post‐N EWTON ian approximation equivalent to E INSTEIN 's equations. The field equations following from Ω (1) (ω 1 , ω 2 ) have a cosmological model with the well known cosmological singularities for T → ± ∞ in case that ω 1 /(1 +3ω 1 +ω 2 ) γ > 0. For ω 1 /(1 +3ω 1 +ω 2 ) ≤ 0 cosmological models with no cosmological singularities exist. From Ω (2) (s̀ 1 , s̀ 2 ) we obtain field equations which at the best give us perihelion rotation 7% above E INSTEIN 's value and light deflection 7% below the corresponding E INSTEIN 's value. But in that case we are able to show the existence of a cosmological model without any cosmological singularity.